Drawing sheet glass



J. B. SMALL ET AL DRAWING SHEET GLASS Filed May 9, 1924 5 O\. fifl w 5am 3 M m w. F 5 m m mm r i W A E i p 5 r r J 4 i i t 6 7 I 3 Patenteduly I 5, 1927.

' UNITED STATES- PATENT OFFICE.

JAMES B. SMALL AND FRANK J'.. KINCAID, OF CHARLESTON, WEST VIRGINIA, AS-

SIGNORS TO THE LIBBEYF OWENS SHEET GLASS COMPANY, OF TOLEDO, OHIO, ACOR- PORATION or oI'rIo.

vionevvma smear GLASS.

Application filed May 9, 1924. Serial No. 711,975.

This invention relates to the art of drawing sheet glass, and moreparticularly to an improved process and apparatus for more rapidlyconditioning the molten glass for 5 the sheet drawing operation, andthus permitting an increased drawing rate, and hence increasedproduction.

In the system of drawing sheet glass substantiallv set forth in theColburn Patent,

1 1,248,809, granted December 4,1917 a mass of. molten glass iscontinuously produced in a tank furnace from which it flows into ashallow receptacle or draw-pot. A continuous sheet of lassis drawnupwardly from 1 the surface 0 the molten glass in the drawpot, thenbent' while still somewhat plastic about a cooled bending roller andcarried away horizontally through -an-; annealing leer. The surfaceglass adjacent the sheet source is, exposed to the cooling influence ofthe air, and heat-absorbing shields are placed closely adjacent thesurface glass at each side ofthe sheet source to protect the sheet fromheated gases from the furnace, 2 and also to absorb heat from the.surface glass flowing thereunder into the sheet source. By this meansthe molten glass is rapidl chilled just prior to being drawn into s eetform, to reduce it to the proper so drawing temperature. i

Accordin to the present invention an additional coo er or heat-absorbingbody is ositioned closely adjacent the surface of t at portion of themolten glass whlchis flowing :5 from the glass-producing tank into thereceptacle from which the sheet is drawn.

This additional cooling body functions to rotect the surface glass inthe draw-pot from the direct action of heated gases from the furnace,and also by rapidly absorbing heat from-the surface strata ofthe-flowing glass rior to its entrance to the draw-pot expedltestheconditioning of the glass in the pot and crmits 'a more re id withdrawalof glass t ere-from in sheet orm.

The objects and advantages of the invention will be more clearlyunderstood from the following detailed description of one approved formof the ap aratus.

' In the accompanying rawings:

' Fig. 1 is a longitudinal vertical section I through those portions ofthe sheet-producing mechanism directly concerned with the presentIHVGIlblOIL' Fig. 2 is a transverse vertical section taken substantiallyon the line 2-2 of Fig. 1.

Fig. 3 is a diagrammatic plan, on a smaller scale, of the aboveapparatus in connection with the glass-producingfurnace.

The glassroducing materialsare inserted into the urnace 1 throughdoghouse 2,

reduced in the melting and 3 of the furnace to molten gllass, thismolten glass then flowing throu the refining end 4 of the furnace intothe smaller and shallower so-called cooling tank 5,; From thecooling-tank 5 the the molten glass 10 in cooling tank 5. From thecoolingtank the glass 10 flows under the jack-arch 11 into receptacle 6,and all of the surface lass in receptacle 6, except the comparative ynarrow transverse strip from which sheet 7 is drawn upwardly, isenclosed by the cover-tiles 12 and 13. At each side of sheet 7 a hollowmetallic water-cooled shield 14 is placed with its lower ed e closelyadjacent to the surface of the molten pool 8. These -shields or coolers14 serveto rotect the sheet source from heated gases owing'out under theli tiles 12 and 13 and at the same time rapid y absorb heat. from thesurface glass which asses under the lower edges of the coolers, t usreducing this glass to the proper temperature to be drawn into sheetform.

At 15 are indicated a pair of small sheet edge grip ing rollers whichfunction to maintam t e proper width of the sheet as,

described more 1n detail in the Colburn patent referred to hereinabove.A heating chamber 16 beneath draw-pot 6 prevents excessive cooling ofthe lower strata of the glass in molten pool 8.

Accordin to the present invention an additional coo er or heat-absorbingbody 17 is positioned closely adjacent the surface of molten glass 10ust before it passes under jack-arc 11 into the draw-pot 6. In the formhere shown. this cooler comprises a comparatively large hollow tubularmetallic casing 18, supported at its ends by pipes 19 and 20. A coolingfluid such as water continuously flows in through pipe 19 at one end ofthe casing and out through pipe 20 at the other end. As here shown pipe20 loops-back above the casing 18 as shown at 21, whereby the inlet andoutlet water connections are both positioned at the same side of thetank. Obviously, the upper return pipe 21 could be omitted and the Waterallowed to flow out at the opposite side of the tank.

The cooler 17 serves to block to a. large extent one end of the assage22 beneath jack-arch l1 and thus ecrease the flow of heated ases fromthe furnace into the space above the molten pool 8 in draw-pot 6. At thesame time cooler 17 wiii absorb heat from the upper strata of th. moltenglass 10 flowing thereunder, and assist the coolers 14 in reducing thisglass to the proper working temperature. in this way sheet? may bewithdrawn from pool 8 at a more rapid rate and the productive capacityof the ma chine is materially increased.

It is not essential that cooler 17 be located at the exact point heredisclosed. It might be positioned at the other side of jack-arch 11, orbeneath the jack-arch. or at any convenient point over the inflowingglass between the tank and draw-pot 6.

Claims:

1-. In the method of drawing sheet glass, wherein molten glass iscontinuously flowed from a tank furnace into a shallow receptacle, anddrawn away therefrom in sheet form, the process of removing heat fromthe menace glass as it flows into the receptacle by placing aheat-ahsorhing loody closely adjacent the surface of this glass.

2. In the method of drawing sheet glass, wherein molten glass iscontinuously flowed from a tank furnace into a shallow receptacle, anddrawn away therefrom in sheet form, the process of removing heat fromthe surface glass l'lowin into the receptacle by placing a heat-absoihing'hody closely au acent the surface of this glass, prior to itsentrance to the receptacle.

3. In sheet glass drawing mechanism, a receptacle containing a pool ofmolten glass a tank furnace in open communication with the receptacle atone side thereof, means for drawing a glass sheet from the surface ofthe pool, means at either side of the sheet source for cooling thesurface glass, and an additional cooling means abore the surface oftheglass flowing into the receptacle from the furnace, the latter coolingmeans comprising a hollow metallic casing through which a circulation ofcooling fluid is maintained.

t. In themethod of drawing sheet glass wherein molten glass iscontinuously flowed from a tankfurnacc into a shallow receptacle, anddrawn therefrom in sheet form, the process of removing heat from the.glass at the point substantially where it enters the receptacle byplacing a heat absorbin body closely adjacent the surface of this g ass.

Signed at Charleston. in the county of Kanawha and State of WestVirginia, this 5th day of May, 1924.

JAS. B. SMALL. FRANK J. KINCAID.

